This invention relates to a spinning machine comprising several spinning stations, which each contain a drafting unit, comprising depositing sites for cans containing sliver, and comprising transport devices containing delivery rollers for the transport of the slivers from the cans to the spinning stations.
In the case of a spinning machine of this type (British Patent Document GB-PS 10 15 780), which is constructed as a ring spinning machine, the transport device has two transport belts for each spinning station. These transport belts form a pair of transport belts which receive and transport a sliver between one another. Directly in front of the drafting unit, the transport belt winds around a drivable delivery roller. The delivery roller can tap its drive by way of a frictional wheel selectively from the lower feeding cylinder of the pertaining drafting unit or--for an accelerated first time feeding of a sliver--from a driving roller which can be driven much faster. A stopping of the delivery rollers is not intended.
In an older German Patent Application P 41 11 000.5, which is no prior publication, it was suggested, for the first-time feeding of the slivers, to jointly stop the delivery rollers of all spinning stations, independently of the drafting units.
It is an object of the invention to be able to stop the sliver supply of a single spinning station in the case of a spinning machine of that above-mentioned type.
This object is achieved according to preferred embodiments of the invention in that the delivery rollers of a drafting unit at a single spinning station can be stopped independently of the delivery rollers of other spinning stations and independently of the pertaining drafting unit.
As a result, it is possible to interrupt the supply of sliver to the disrupted spinning station without having to intervene in the drafting unit in the case of a yarn breakage. This is advantageous in that the known sliver stopping devices on drafting units present serious problems and usually have the result that, after a stopping of the drafting units, the spinning cannot easily be continued.
Advantageously, the delivery rollers of several spinning stations are connected to a central drive from which they can be drivingly connected and disconnected separately. This is achieved according to certain preferred embodiments by arranging the delivery rollers on a drivable shaft which extends in the longitudinal direction of the machine and connecting them with this shaft by way of a coupling. In the case of such a development, the spinning operation can easily be continued after an interruption of the sliver supply.
In an advantageous development of the invention, it is provided that the delivery rollers are each assigned to a transport belt transporting at least one sliver. In the case of such a solution, the whole distance between the sliver supply can and the pertaining spinning station can be bridged by means of a single delivery roller because it is the transport belt that guides the slivers. Therefore, the transport as a whole is also interrupted and can be continued at any time without the occurrence of faulty drafts anywhere in the sliver. As a result, it is possible to securely transport also very fine slivers, that is, slivers of sizes from Nm 0.3 to 0.8 without the risk of drafts during the operational transport. In the case of ring spinning machines, the machine that is normally connected in front of the ring spinning machine, specifically the flyer, will then not be necessary. Since the otherwise customary flyer twist is absent, the slivers can be drawn more in the drafting units so that ordinary three-cylinder drafting units can be used.
Advantageously, the delivery rollers are connected directly in front of the pertaining drafting unit. The transport of the slivers will then be more easily controllable, and it is expedient to let the delivery rollers run slightly more slowly than the feeding roller of the drafting units arranged behind them so that a slight tensioning draft is created which, however, does not result in a faulty draft.
In a further development of the invention, it is provided that the delivery rollers can be stopped from several operating sites. This is particularly recommendable when the cans are not deposited not on the floor, but rather above the spinning machine in an elevated manner on a platform or even on another floor.
A preferably optical sensor is expediently assigned to the delivery rollers for determining the presence of sliver. This is particularly useful when sliver is transported for the first time, for example, after a batch change. Since the transport of the sliver is very slow upstream of the drafting unit, it takes several minutes until a new sliver has passed through the transport path to the pertaining spinning station. It cannot be assumed that an operator is present at the spinning station exactly when the sliver arrives there. For this reason, it is useful to interrupt the transport of the sliver as soon as the sensor reports the presence of a new sliver at a spinning station. The transport can then be switched on again manually after the sliver is introduced into the drafting unit.
The delivery rollers are expediently connected with the shaft that drives them by way of a torque limiter. As a result, it becomes possible to simply stop the delivery roller while the shaft driving it continues to rotate.
A cam, which rotates along with the delivery rollers and to which a stop can be applied for the stopping of the delivery roller, is advantageously assigned to the delivery rollers. As a result, it becomes possible in a simple manner to stop the delivery roller while the drive shaft continues to rotate.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.